Seal for chutes of concrete mixers



Nov. 30, 1948. H. c. PETERS 2,454,940

SEAL FOR CHUTES OF CONCRETE M IXERS Filed July 27, 1946 a'sneets-sneei 1.lllum il Nov. 30, 1948, v H. c. PETERS 2,454,940

I SEAL FOR CHUTES OF CONCRETE MIXERS Filed July 27, 1946 2 Sheeis-Sheet2 HHHIHI' QJIIFI,

Patented Nov. 30, 1948 UNITED" STATES 8.:Claimsr. (Cl. 259-161) E Thisinventionrelates to concrete mixers-and refers particularly toa:combination 1 feed chute and closure for-truok type concretemixers: V

In truck-mixers especially those of the high discharge-type, the-drum isloaded and-discharged. throughitselevated' open end at the rearof thetruck. To enable rapid charging of the drum, asubstantially funnel-likefeed chute is provided todirect the-aggregates through the mouth of thedrum provided by its open rear end. Discharging ofthe drum contents iseffected by reversingthe direction of rotation of the drum whereupon thespirally arranged mixing blades in'thedrum convey the concreterearwardlyto spillkacross the-lower edge of its open end intoanappropriate discharge chute.

Inasmuch as-it is preferable to have the drum closed ascompletelyaspossible during transit, acover. is generally provided for the top ofthe funnel-like feed chute and the space between its discharge end andthe edge of'the drum-is closed by an annular wall carried bythe feedchute-and engaging the edge of the drum.

This annular wal-lconsists of a central'nonrotatable part fixed to thefeed chute and an outer rotatable part adapted to turnwith the drum. A-free running bearing is, therefore, provided between the centralnon-rotatable and outer rotatable parts of the annular wall. Theprovision of such-a bearing is a relatively simple matter, but.considerable difficulty has beentexperienced in the: past in' keeping itfree from dirt and grout.

Many differenttypes of seals have: been proposed; in g the past topreclude; theentry of grout 'andioreignxmatter into the bearingfrominside.

thezzdrum; but forone reason oranother all past expedients: directed to'this purposev havenbeen:

inadequate.

It is, therefore, the chief object of this invention to provide, a;free; running seal between the. central non-rotatable and the outerrotatable partsof the drum closure in a truck type concretemixerwhichwill remain effectiveto pre-- cludethe passage of-grout and foreignmatter.

intothebearing between the central, non-rotatableand the outer annularpart, notwithstanding theexcessive, wear to which equipment f th typeissubjected.

Another object of this: invention is'to provide.

ausealfor the purpose described, whichv is simplein. construction and sodesigned and constructed: thatthe efiectiveness of thesea-l is not,dependout upon the degree of pressure of the rotating;

elements against the drum opening.

Another object of .this invention is to provide a seal of the characterdescribed which will re-, main effective for'the life of the equipmentby virtueof the fact that wear which takes place therein-merely improvesthe lit oi-the parts:

2. Withthe above and other objects in view which will appear as thedescription proceeds; this invention residesin thenovel construction,combination and'a-rrangement of parts substantiallyas hereinafterdescribed andmore particularly;

defined bythe appendedclaims; it being understood that such changes intheprecise embodiment of the hereindisclosedinvention may be made ascome within the scope of the claims.

The accompanying drawings illustrate one complete exampleof the physicalembodiment of the invention constructed-according to the'best mode sofar devised for-the practical application of the principles thereof, andin which:

Figure 1 is a View in side elevation withparts broken" awayandin-section illustrating-the rearend portion of a-truck type concretemixer embodying t'his invention;

Figure 2"is a detailsectional view-through the seal and bearingbetweenthe rotatable andnerrrotatable parts ofthe closure;

Figure3-is a-rear view of the complete structureshown in Figure 1;

Figure 4 is a fragmentary detail view illustratinga portion of one ofthe elements of the seal between the rotatable and non-rotatable closureparts;

Figure 5 is a cross sectional view through Figure 4 onthe plane of theline 5+5; and

Figure-6 is 'anexploded perspective crosssec tional View through theelements which coact'tog;

form the free-running seal.

Referring now more; particularly to the accompanying drawings; inwhichlike numerals indicate likeparts, the-numeral 5' designa-tes. the

rotatable mixing drum of a truck type concretemixer-Whichasiscustomary-in the high discharge mixers now ini eneraluse, revolves about" The elevated rear end of the an inclined axis-.-drum -is open and; serves as a common charging anddischa-rgingmouth for,the drum. A drip ring 6- fixedthereto provides a solid finishmachinededge f or-the mouth of the drum.

Inasmuch as the invention is' not'con'cerned" with the -ma-nner in'which the-drum is mounted and driven thesefeatu-resare not illustrated.It is commonknowledgeto those-skilled in this art thatthecOn-tents ofthe drum are-discharged by r the action of the mixing blades (not shown)upon reverse rotation of the drum, whereby the concretecontained-therein is advanced to and;-

spi-lledout of the mouth of the drum;

Charging otthe drum isefiected through afunnel-li-ke hopperor feedchute- I pivotally mounted from the frame 8 of the supporting structureby means of arms 9.

chute-as at IO and their-upper inner ends are The outer ends n the arms9. are pivotall "connected; to the feed:

charging position, shown in Figure 1, and an elevated dischargingposition by means of mechanism (not shown) acting through a connectingrod I2. The manner in which the feed chute is mounted and swung to andfrom its charging position is more particularly described in the patentto R. J. Barnes, No. 2,374,912.

The open top of the feed chute is adapted to be closed by a hinged coverI3 so that when the feed chute is in its charging position and the coverI3 is down, it serves to close the central portion of the mouth of thedrum. The annular space between the discharge end of the feed chute andthe edge of the drum is closed by an annular wall structure consistingof a non-rotatable annular plate I4 fixed to the feed chute and arotatable annular plate or ring I5 mounted to revolve about thenon-rotatable plate by means of a free running bearing structureindicated generally by the numeral I6. feed chute is in its closedcharging position, the rotatable annular ring-like part I5 bears againstthe drip ring 6 to turn with the drum.

The bearing structure I6 by which the nonrotatable and rotatable partsI4 and I5 are connected for free relative rotation comprises a ringmember I! bolted to the peripheral portion of the non-rotatable part I4and a ring member I8 bolted to the inner peripheral portion of therotatable part I5. The rings I1 and I8 have complementary flanges formedwith mutually engaging right angularly disposed surfaces I 9 and 20. Thelatter cooperates with a retaining ring or flange 2| fixed to therotatabe ring I8 to embrace a flange of the non-rotatable ring I I andthus hold said ring members together. Lubricant is fed to the bearingsurfaces I9 and/or through one or more grease fittings 22 andappropriate passages.

While the mutually engaging bearing surfaces I9 and 20 provide anexcellent bearing for the rotatable closure part I5 and assures itsfreedom to turn with the drum, these bearing surfaces would soon beruined by the abrasive action of grout from inside the mixing drumunless the grout is effectually excluded from the bearing. The provisionof a seal which will satisfactorily guard against the passage of groutand other foreign matter from inside the drum to the free runningbearing is the chief purpose of this invention.

Thus the rotatable ring member I8 and an inner ring member or flange 23bolted to the nonrotatable ring member II have adjacent conical surfaces24 and 25 respectively. These conical surfaces have their large diameterends in juxtaposition and hence define an annular V-shaped grooveopening radially inward to an annular lubricant reservoir 25'.

The reservoir 25 is formed conjointly by the ring members I8 and 23, andis of a size to receive an expanding split spring ring 26, the outerperipheral portion of which has a cross sectional shape corresponding tothat of the V-shaped groove. Thus the expanding split spring ring has.

conical surfaces 21 to engage the conical surface 24 and 25 with a snugsurface-to-surface engagement, such engagement being maintained by theinherent resilience of the spring ring 26.; The lubricant reservoir 25'is adapted to be;

and .t e s m mb r i nd ?3 a b kept1uh.-;

Thus when the V and the inside of the drum, the passage of grout andforeign matter from inside the drum to the bearing is effectuallyprecluded. The opening 3| between the ends of the expanding split springring is ordinarily so slight that there is little danger for grout topass through it. 7

Positive assurance against even this slight leakage is obtained by abridgingpiece 32 slidably received in slots 33 in the ends of the springring as shown in Figures 4 and 5. This bridging piece is, of course,shaped to have its side edges lie flush with the conical surfaces of theexpanding split spring ring.

From the foregoing description taken in connection with the accompanyingdrawings, it will be readily apparent that this invention provides apractical wholly satisfactory free running seal between thenon-rotatable and rotatable parts of the closure or door for the mouthof a truck type concrete mixer and that the incorporation of the seal ofthis invention involves no radical change from a design found to becommercially acceptable.

What I claim as my invention is:

1. A closure for the mouth of a rotatable concrete mixing drum,including a non-rotatable part covering the central portion of the mouthof the drum, an annular rotatable part surrounding the non-rotatablepart and engageable with the edge of the drum, and a bearing betweensaid parts permitting free rotation of the rotatable part relative tothe non-rotatable part, characterized by the provision of: a seallocated between the bearing and the inside of the drum to prevent thepassage of grout and liquid to the bearing from inside the drum,comprising adjacent annular surfaces on the rotatable and non-rotatableparts shaped to form an annular groove having diverging sides and openinradially inwardly; and an expanding spring ring in said groovemaintained in contact with the diverging sides thereof by its owninherent resilience.

2. A closure for the mouth of a rotatable concrete mixing drumcomprising: an inner nonrotatable and an outer rotatable part, saidparts conjointly forming the closure for the mouth of the drum; meansconnected with the non-rotatable inner part for moving the closure toand from a closed position at which its outer rotatable part engages theedge of the drum to rotate therenon-rotatable part; adjacent annularmembers on said-parts located between said bearing and the inside of thedrum, said members having annular surfaces coacting to form an annulargroove; and a spring ring seated in said groove and maintained in snugengagement with the walls thereof by the inherent resilience of thespring ring.

3. A closure for the mouth of a rotatable concrete mixing drum of thetype charged and dis-v charged through the same mouth and wherein"charging is effected through a feed chute mounted adjacent to the mouthof the drum for swinging to and from a position projecting into thecentral part of the mouth so that said feed chute covers the centralpart of the mouth of the drum when in its charging position, and whereinthe annular space between the feed chute and the edge of the drum isclosed conjointly by a nonrotatable part encircling and carried by thefeed chute and a rotatable part rotatably joined with and encirclingsaid non-rotatable part and engaging the edge of the drum to turntherewith, characterized by the provision of: a seal for the jointbetween the non-rotatable and rotatable parts comprising, annularmembers on said parts disposed between said joint and the inside of thedrum and having adjacent conical surfaces coacting to form an annulargroove with diverging sides, and a spring ring received in said grooveand by its inherent resiliency maintaining snug engagement with thewalls thereof.

4. In a concrete mixer: a rotatable mixing drum having an open endproviding a mouth through which the drum is charged and discharged; acombination feed chute and closure for the mouth of the drum including afunnellike feed chute, a non-rotatable annular wall encircling and fixedto the discharge end of the feed chute, and an annular rotatable partrotatably joined with said wall and engageable with the edge of the drumto turn therewith; annular members on said rotatable part and thenonrotatable wall disposed intermediate the joint therebetween and theinside of the drum, said members having adjacent annular surfacescooperating to define an annular groove; a spring ring seated in saidgroove and urged into snug engagement with the surfaces thereof to forma free running seal between said annular rotatable part and said wall;and means for moving said combined feed chute and closure to and from aclosed position at which its annular rotatable part engages the drum toturn therewith.

5. In a concrete mixer having a rotatable mixing drum adapted to becharged and discharged through an open end thereof, a combination feedchute and closure for said open end of the drum, including a funnel-likefeed chute, a non-rotatable annular wall encircling and fixed to thedischarge end of the feed chute, and an annular rotatable part rotatablyjoined with said wall and engageable with the edge of the drum to turntherewith: a free running seal between said annular rotatable part andsaid non-rotatable wall, comprising cooperating annular members on saidwall and the rotatable part having adjacent conical surfaces thereonwith the large diameter ends of said surfaces in juxtaposition andradially outermost so that said conical surfaces conjointly form aradially inwardly opening V-s-haped groove; and an expanding springringseated in said groove, said ring having its outer peripheral portionV-shaped to fit the walls of the roove with a surface-to-surface contactand be maintained in snug engagement therewith by the inherentresilience of the spring ring.

6. In a concrete mixer having a rotatable mixing drum adapted to becharged and discharged through an open end thereof, a combination feedchute and closure for said open end of the drum, including a funnel-likefeed chute, a nonrotatable annular wall encircling and fixed to thedischarge end of the feed chute, and an annular rotatable part rotatablyjoined with said wall and engageable with the edge of the drum to turntherewith: a free running seal between said annular rotatable part andsaid non-rotatable wall, comprising, a stationary metal ring fixed tothe non-rotatable annular wall, said stationary ring having a smoothfinished annular surface; a rotatable metal ring fixed to the annularrotatable part, said rotatable ring having a smooth finished annularsurface; said rings being coaxial and adjacent to each other and beinginterposed between said joint and the inside of the drum with theirsmooth finished annular surfaces in juxtaposition; a metal sealing ringbetween said smooth finished annular surfaces; and means for resilientlymaintaining the sealing ring in snug engagement with said smoothfinished annular surfaces, said sealing ring being free to turn with therotatable ring or stand still with the stationary ring.

7. A closure structure of the character described comprising: a centralnon-rotatable part; an annular rotatable part; a joint between saidparts providing for free rotation of the rotatable part relative to thenon-rotatable part; means on said parts lying between said joint and theinside of the drum conjointly forming an annular substantially V-shapedgroove opening radially inwardly; a metal spring ring seated in saidgroove, said ring having its outer circumferential portion V-shaped incross-section corresponding to the angle between the walls defining theV-shaped groove so as to have snug surfaceto-surfa-ce engagementtherewith; means on the non-rotatable and rotatable parts jointlydefining an annular lubricant reservoir opening to the V-shaped groove,and embracing the radially inner portion of the spring ring; and meansfor introducing lubricant into said reservoir.

8. A closure structure of the character described comprising: a centralnon-rotatable part; an annular rotatable part; a joint between saidparts providing for free rotation of the rotatable part relative to thenon-rotatable part; means on said parts lying between said joint and theinside of the drum conjointly forming an annular substantially V-shapedgroove opening radially inwardly; an expanding metal spring ring seatedin said groove, said ring having its outer circumferential portionV-shaped in cross-section corresponding to the angle between the wallsdefining the V-shaped groove so as to have snug surface-to-surfaceengagement therewith; means on the non-rotatable and rotatable partsjointly defining an annular lubricant reservoir in which the radiallyinner portion of the spring ring is located; means for introducinglubricant into said reservoir; said spring ring being split and itsadjacent ends having aligned slots in the outer portions of theirV-shaped cross-section; and a bridging piece slidably received in saidslots and extending across the space between the ends of the ring.

HARRY C. PETERS.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,265,751 Ball Dec. 9, 19412,265,752 Ball Dec. 9, 1941 2,267,801 Peters et a1 Dec. 30, 19412,374,912 Barnes May 1, 1945

